1. Field of the Invention
The present invention generally relates to a chiropractic percussor apparatus for use in a chiropractic treatment to apply percussion-type repetitive force to the human body and, more particularly, is concerned with a chiropractic percussor apparatus having a compact percussion head assembly that is centrally attached to a force-transmitting reciprocatory push rod of the apparatus.
2. Description of the Prior Art
Chiropractic adjustments of the spinal vertebrae of a human body involve the application of pressure or force in a known manner directly to the human body by the hands of a chiropractor or by a chiropractic percussor apparatus used by the chiropractor. An example of such chiropractic percussor apparatus found in the prior patent art is the one disclosed in U.S. Pat. No. 4,079,733 to Denton et al.
Another example of a prior art chiropractic percussor apparatus is the one illustrated in FIGS. 1 to 3. The apparatus of FIGS. 1 to 3, generally designated 10, includes a main housing 12, an electric motor 14 in the main housing 12, and a speed adjustment knob 16 and an on/off push button 18 on the main housing 12. The main housing 12 defines an interior cavity 20 and is adapted to be gripped by a user to hold the apparatus 10 during use. The electric motor 14 is disposed in the cavity 20 of the main housing 12 and has a rotary output shaft 22 extending from front ends 14A, 12A of the motor 14 and main housing 12. The speed adjustment knob 16 and on/off push button 18 are mounted to a rear end 12B of the main housing 12 and connected to the motor 14 such that by turning the knob 16 and/or depressing the button 18 the rotational speed of the output shaft 22 can be varied and/or the motor 14 can be alternately turned on and off. The electric motor 14 receives electrical power via an electrical cord 24 connected to a separate power conversion module 26 which, in turn, is plugged into a conventional AC outlet.
The apparatus 10 of FIGS. 1 to 3 further includes an extension housing 28, a cam 30 eccentrically mounted on an outer end 22A of the rotary output shaft 22 of the motor 14, an elongated push rod 32 mounted at an inner end 32A on the cam 30, a flexible coupler assembly 33 coupling an outer end 32B of the push rod 32 to an outer end 28A of the extension housing 28, and a percussion head assembly 34 supported on the outer end 32B of the push rod 32. The extension housing 28 is attached at an inner end 28B to the front end 12A of the main housing 12 and extends in a transverse relationship thereto and outwardly therefrom such that the main and extension housings 12, 28 together have a L-shaped configuration. The extension housing 28 further defines an interior chamber 36 and its outer end 28A has an annular shape and forms an opening 38 and is spaced from the front end 12A of the main housing 12. The push rod 32 extends through the extension housing 28 from the cam 30 to the opening 38 at the outer end 28A of the extension housing 28. The inner end 32A of the push rod 32 has an opening 40 which receives therein the cam 30 such that the push rod 32 at its inner end 32A surrounds the cam 30. The flexible coupler assembly 33 includes an annular clamp 42 and a circular diaphragm 44 provided at the outer end 28A of the extension housing 28 and coupling the outer end 32B of the push rod 32 thereto so as to permit the outer end 32B of the push rod 32 to undergo reciprocal lengthwise movement and wobbling side-to-side movement relative to the outer end 28A of the extension housing 28. The diaphragm 44 is formed by a flexible sheet of rubber and is clamped about its peripheral portion 44A between the annular clamp 42 and an annular flange 46 on the outer end 28A of the extension housing 28. The annular clamp 42 is secured to the annular flange 46 by a plurality of screws 48 extending through the peripheral portion 44A of the diaphragm 44. The diaphragm 44 also has a main portion 44B which extends across the opening 38 of the outer end 28A of the extension housing 28 which is adjacent to an inner surface 44C of the diaphragm 44 and across a central bore 50 through the annular clamp 42 which is adjacent to an outer surface 44D of the diaphragm 44.
The percussion head assembly 34 of the apparatus 10 includes a coupler body 52 and a contact pad 54. The coupler body 52 extends through the central bore 50 of the annular clamp 42 to the main portion 44B of the diaphragm 44 and outwardly from the annular clamp 42. The coupler body 52 has a plurality of passages 56 defined therethrough radially outwardly from and circumferentially spaced about a central threaded hole 58 defined through the coupler body 52. A plurality of fasteners 60 are inserted through the passages 56 of the coupler body 52 and screwed into holes 62 tapped in the outer end 32B of the push rod 32 such that the main portion 44B of the diaphragm 44 is clamped between the coupler body 52 and the outer end 32B of the push rod 32 with the main portion 44B of the diaphragm 44 extending radially outwardly beyond holes 44E in the diaphragm 44 where the fasteners 60 pass through the diaphragm 44. The contact pad 54 has a stiff circular base plate 64, a fastener 66 fixedly mounted centrally thereon and extending outwardly from an inner surface 64A of the base plate 64, and a disc 68 of resilient compressible foam material attached to an outer surface 64B of the base plate 64. The fastener 66 removably screws into the central threaded hole 58 of the coupler body 52 so as to mount the contact pad 54 on the outer side 52A of the coupler body 52 as the inner side 52B of the coupler body 52 is held against the main portion 44B of the diaphragm 44 by the fasteners 60.
Upon depressing of the button 18, rotation of the output shaft 22 of the motor 14 occurs and the cam 30 thereon is eccentrically rotated causing the push rod 32 to undergo a reciprocal lengthwise movement and a wobbling side-to-side movement in the extension housing 28 so as to correspondingly impose percussive and massaging actions on a surface, such as a part of the human body, against which the contact pad 54 is applied by the user holding the apparatus 10.
A problem of this prior art apparatus 10 is the way in which the diaphragm 44 of the percussion head assembly 34 is secured to the outer end 28A of the extension housing 28 and the outer end 32B of the push rod 32. Such securement which does not permit any flexing at the peripheral and main portions 44A, 44B of the diaphragm 44 leaves only a narrow annular band-like portion 44F of the diaphragm 44 extending between and interconnecting the peripheral and main portions 44A, 44B where flexing of the diaphragm 44 can occur to accommodate the reciprocatory and side-to-side motions of the push rod 32. The provision of only the narrow band-like portion 44F for flexing of the diaphragm 44 overly restricts the size of the path of motion of the outer end 32B of the push rod 32 and thereby of the contact pad 54 for delivery of the percussive and massaging actions on the human body.
Consequently, a need exists for an innovation that will provide a percussion head assembly that will overcome the aforementioned problem of the prior art chiropractic percussor apparatus without introducing any new problems in place thereof.
The present invention provides an enhanced chiropractic percussor apparatus designed to satisfy the aforementioned need. The apparatus of the present invention has a compact percussion head assembly having a diaphragm which is secured to the extension housing and outer end of the reciprocatory push rod of the enhanced apparatus and a contact pad which is only centrally attached to the outer end of the push rod so as to permits a substantially wider annular band-like portion of the diaphragm to flex which, in turn, expands the size of the path of motion of the outer end of the push rod and thereby of the contact pad for delivery of percussive and massaging actions on the human body which are more effective than the corresponding actions delivered by the prior art apparatus. Also, the compact character of the percussion head assembly and its central connection to the end of the reciprocatory rod provides a more reliable and stable assembly than is found in the prior art apparatus.
Accordingly, the present invention is directed to a chiropractic percussor apparatus which comprises: (a) a main housing adapted to be held by a user; (b) an electric motor mounted in the main housing and having a rotary output shaft extending therefrom; (c) an extension housing attached to an end of the main housing and extending outwardly therefrom and having an outer end defining an opening; (d) an elongated push rod eccentrically mounted at an inner end on the rotary output shaft of the electric motor and extending through the extension housing to an outer end of the push rod having a central hole; (e) a flexible coupler assembly supported by the outer end of the extension housing and coupled to the outer end of the push rod so as to permit the outer end of the push rod to undergo reciprocal lengthwise movement and wobbling side-to-side movement relative to the outer end of the extension housing; and (f) a percussion-applying head assembly only centrally attached to the outer end of the push rod at the central hole therein.
The flexible coupler assembly includes an annular flange member attached at an inner surface to the outer end of the extension housing and mounted across the opening thereof. The annular flange member has an aperture receiving the outer end of the push rod and an outer surface facing away from the extension housing. The flexible coupler assembly further includes a diaphragm of resilient flexible material disposed on the outer surface of the annular flange member and having a central aperture. The flexible coupler assembly still further includes means for attaching the diaphragm about a peripheral portion thereof to the annular flange member and for attaching the diaphragm at a central portion thereof about the central aperture thereof to the outer end of the push rod about the central hole in the push rod such that the diaphragm has an intermediate annular portion extending between the peripheral and central portions thereof that is free to flex so as to permit the reciprocal lengthwise movement and the wobbling side-to-side movement of the outer end of the push rod relative to the outer end of the extension housing.
The percussion-applying head assembly includes a pad support member having a plate and a single fastener mounted centrally on the plate and extending outwardly therefrom through the central aperture of the diaphragm and tightly fitted into the central hole in the outer end of the push rod so as to mount the pad support member directly to the outer end of the push rod by the centrally-located single fastener extending through the central aperture in the central portion of the diaphragm. The percussion-applying head assembly further includes a contact pad mounted to the plate of the pad support member such that rotation of the output shaft of the motor causes the outer end of the push rod and the pad support member and contact pad therewith to undergo the reciprocal lengthwise motion and the wobbling side-to-side motion so as to impose percussive and massaging actions on a surface against which the contact pad is applied by the user.
These and other features and advantages of the present invention will become apparent to those skilled in the art upon a reading of the following detailed description when taken in conjunction with the drawings wherein there is shown and described an illustrative embodiment of the invention.